[Smoking, fertility and very preterm birth]

In France, many couples in procreating age continue to smoke, despite recommendations to stop smoking before or during pregnancy. We reviewed the epidemiological associations between maternal or paternal smoking and both infertility and very preterm birth. It appears clearly that maternal smoking impairs natural and assisted fecundity. Furthermore, maternal smoking enhances the rate of ectopic pregnancies and spontaneous abortions. The role of maternal smoking on very preterm birth before 33 weeks of completed gestation appears in recent population based-study or case-control studies that include several hundred very preterm neonates. But the role of smoking on very preterm birth among hypertensive mothers and primiparae is still debated. The detrimental effect of smoking on fecundity appears to be reversible when the mother and father stop smoking. The real effect of interventions promoting cessation of smoking during pregnancy in reducing the rate of very preterm births remains to be studied.